Cal. Penal Code § 462.5

(a) Except in unusual cases where the interests of justice would best be served if the person is granted probation, probation shall not be granted to any person who is convicted of a felony custodial institution burglary. In any case in which a person is convicted of a misdemeanor custodial institution burglary, such person shall be confined in the county jail for not less than 90 days nor more than one year except in unusual cases where the interests of justice would best be served by the granting of probation. (b) As used in this section, “custodial institution burglary” shall mean a violation of Section 459 on the grounds of any jail or correctional institution with the intent to steal items to use or convert for use as weapons, escape tools, or intoxicating drugs. (c) If the court grants probation under subdivision (a), it shall specify the reason or reasons for such order on the court record. (d) Any person convicted of custodial institution burglary shall serve his or her sentence, including enhancements, consecutive to any other sentence in effect or pending. The felony sentence shall be calculated under Section 1170.1.